HD700 Review
(Purrin + LFF)
Introduction
Headphone meets are one of the best way to get to know how headphones really sound like. Both LFF and I have regularly attended meets. LFF was one of the organizers of CanJam 2009 and attended meets much more frequently in the past. I have made it a point to attend all major meets in California since February 2011. The number of smaller private mini or micro meets I have hosted or attended is too numerous to count.
Meets are great way to make new friends. There’s a secret advantage to having a few friends who share our passion with the hobby. Since individuals by nature will have different tastes, we create an opportunity to expose ourselves to a much wider variety of gear by borrowing and lending equipment among friends. Such arrangements also enable us to have some “quality time” without the noise and other constraints of larger meets.
Unfortunately, many people cannot make meets. Not every person lives in a highly populated urban area where meets are likely to be scheduled on a regular basis. Short of taking advantage of Internet retailers’ generous return policies (we don’t consider this unethical because they have driven brick-and-mortar stores out of business), people must rely on other persons’ subjective impressions or on comparative objective measurements.
Though certain characteristics of frequency response and CSD plots may correlate with good or bad sound, a substantial amount of exposure to and willingness to study measurements is a prerequisite to seeing how certain patterns correspond with what we hear. Even then, measurements are limited in what they describe, and they are by no means a 100% predictor of whether we will like a headphone or not. They also have the disadvantage of being comparable only with measurements utilizing the same measurement system and methods.
On the other hand, subjective impressions are always biased. In many cases, others opinions may vary wildly from our own. To alleviate this issue, we will draw comparisons of specific aspects of the HD700 with those of other well known headphones, and try to avoid issuing personal opinions or using absolute terms such as “good” or “bad”.
HD700 Frequency Response and CSD Plots
Listening Impressions with Commentary on Measurements
Listening tests were conducted with an Eddie Current Balancing Act amplifier with vintage Osram PX25 DHTs and a Tungsol Black Glass Round Plate 6SN7 and an Objective 2 amplifier with an LM4562 opamp. The PS Audio PerfectWave2 was used as the DAC. A PC running J River MC17 was used as the data source using the PS Audio Bridge (Ethernet DLNA) to feed the DAC. The tubes and opamp chosen above worked well with taking the edge of the HD800's treble, and therefore were also selected for use with the HD700. In addition, a Sony Walkman X and Sansa Clip (with Rockbox installed) were also used.
Upon initial listening, the HD700 appears to be a highly detailed sounding headphone. However with deeper more prolonged analysis, we found this not to be necessarily the case, especially in comparison to other headphones such as the HD650, HD600, or HE500. We are not saying that the HD700 doesn’t have good resolution or isn’t detailed sounding. It very much does; but its rendering of micro-detail is no better than many other mid-fi headphones, and certainly not up to the level of the HD800. It should be noted that the HD700 do sound very clean and clear. Somewhere between the HD650 and HD800.
There are two measurement characteristics which contribute to the HD700's high level of gross detail reproduction: the 5.5kHz peak and 11kHz peak. Peaks near 5kHz give recordings more “edge” and excitement. It’s interesting that another headphone with almost the same exact measurement peak at 5kHz is the Grado RS-1. Many of us who have heard the RS-1 know it to have an exciting sound with a high level of apparent gross detail. Peaks near 11kHz tend to give recordings more definition or sparkle. Other popular headphones which exhibit similar (but not exactly the same) behavior at around 9-11kHz are the Denon D-series and Beyer T1.
HD700 (green) vs. Grado RS-1 (red)
The HD700's 5.5kHz peak is very similar in magnitude and shape to the Grado RS-1's 5kHz peak.
Between the 5.5kHz and 11kHz peaks, there is a rather significant dip. In other words, both peaks are rather narrow, and the treble is very uneven. Because of this, the HD700 can sound either bright or warm depending upon the recording. If a recording with particular traits tends to excite the peaks (drums or percussion instruments tuned to specific frequencies, or vocal overtones in a certain range), then the recording may sound bright or strident. If a recording does not possess traits which excite the peaks, then the HD700 can sound warm. The HD700 often takes on this latter characteristic with non-amplified acoustic instruments used in classical music. It should also be noted out that many classical titles tend to be mastered with a midrange emphasis with some roll off at the bass and treble.
Other headphones, e.g. ATH-AD2000, RS-1, AKG Sextetts, etc, also have a peak (and corresponding ringing) around 4-5.5kHz. Typically, resonances in this area are benign. As mentioned above, a peak around 5kHz tends to give recordings a kick or an edge. However, in the case of the HD700, the high magnitude of this peak combined with the fact that there's yet another sympathetic peak exactly one octave higher at 11kHz makes its effect more noticeable and "augmented".
In essence, if we can isolate (for the sake of argument) just the treble region, the HD700 sounds like the RS-1 in the lower treble, and the Denon D2000 in the mid treble, but with a deep dip in between. Some listeners may find this combination objectionable with extended or even minimal listening. Others may find it engaging, alive, and sparkly. We have no doubt however that the treble character of the HD700 will be a strong point of contention among listeners given individual's sensitivities to treble peaks, preferred listening levels, and favored genres of music.
HD700 (green) vs. HD800 (red)
The HD800's treble is overall brighter but also smoother than the HD700's treble.
Finally, the HD700 are overall (when the peaks and dips are octave smoothed) slightly less bright than the HD800. However the HD700’s uneven treble response lends it a harsher tone than that of the HD800, which has a much smoother response in comparison. Compared to the RS-1, the HD700 does sound much more refined, clearer, and less raw from the upper midrange to the treble.
RS-1 CSD Plot (Midrange to Treble) vs. HD700 CSD Plot (Midrange to Treble)
The HD700 has a much cleaner floor than the RS-1
The HD700 has a slightly U-curved frequency response. The magnitude of the U-curve is not quite to the extent of the Denon D-series in that the Denons have much more mid to sub-bass than the HD700. Also the treble lift of the Denon D-series starts earlier at 3kHz and its rise is much more gradual than that of the HD700.
In our experience, we feel that more gradual smoother changes in frequency response is more cohesive sounding (for lack of a better term.) In our opinion, the HD700 does lack that last bit of cohesiveness with its midrange transition to the treble. This lack of cohesiveness is very difficult to describe and best experienced in comparison with other headphones which do have a smoother response in this range. At the strong risk of issuing a personal opinion, we do feel it sounds “odd”.
HD700 (green) vs. Denon D7000 (red)
The Denon has more mid to sub bass than the HD700
The Denon's treble rise has a shallower slope than the HD700's
Despite similarities in measured bass response to the HD800, the HD700 do subjectively sound quite a bit warmer. I suspected this was the result of increased second harmonic distortion in the bass. Essentially second harmonic distortion is a doubling effect in which a tone exactly one octave higher but at lower magnitude is reproduced along with the original tone. This doubling effect gives the HD700 an emphasized, reinforced bassier sound compared to the HD800.
HD700 non-linear distortion 50Hz @90db.
Second harmonic at -28db. Third harmonic at -45db.
The higher second harmonic gives the bass a more reinforced sound compared to the HD800.
HD800 non-linear distortion 50Hz @90db.
Second harmonic at -44db. Third harmonic at -38db.
According to the measurements (50Hz tone at 90db) above, the HD800 has a little bit of third-order harmonic distortion, but very little to no second order distortion. The HD700 has the same level of third-order harmonic distortion, but with a moderate amount of second order harmonic distortion.
Conclusion
In conclusion, we will not be making any absolute judgements about this headphone, but instead offer some of our insights on the types of listeners who may (or may not) appreciate the sound of this headphone. In addition, we have indicated several other headphones to compare specific aspects of the HD700 with.
- The HD700 may be bridge to Sennheiser for the Grado fan. Sennheiser had started on the path of more upper-midrange excitement (in small doses) with the HD558 and HD598, and now they’ve gone all the way. To those who like the RS1, this may be an interesting listen.
- The HD700 may also prove to be an interesting alternative to (but not an amalgamation of) the HD800 and HD650. Many Sennheiser adherents have found the HD650 too laid back and the HD800 too bright. The HD700 takes us for an unexpected M. Night Shamalan twist. It adds warmth to the HD800, tighter bass than the HD650, a U-curved response, and a good splash of upper midrange forwardness and excitement not found on any other Sennheiser.
- Newer people (or experienced people looking for a change) may find the HD700 to be an exciting, vivid, clear sounding, and detailed fun listen.
- People who have grown to appreciate neutrality, naturalness, smoothness, and evenness of frequency response should stay away from this headphone.
- People who are sensitive to high frequency peaks (there are two within the audible range unless you can really hear 20kHz), should also stay away from this headphone.
- People who are waiting for the Sennheiser headphone with the HD650’s tonality and a good portion of the HD800’s true resolving capabilities should also stay away.
Concerns
Because of the high amplitude and sharpness of the peaks at 5.5kHz and 11kHz, we urge listeners to be careful when listening at loud volume or for prolonged periods of time. Most people will adjust their volume to set the midrange to a certain level. The 5.5kHz peak is 6db above the level at 1kHz. This is a doubling of volume intensity. As an example, let's compare the HD700 to the ESP950, a headphone which I've listened to at loud levels ~85db for prolonged periods.
HD700 (green) vs. ESP950 (red)
At 5.5kHz, we can clearly see that the HD700 is 10db louder than the ESP950. Noise induced hearing loss (NIHL) has been shown to manifest as notches from 3kHz to 6kHz. We are especially concerned with those listeners who do not notice or do not mind the treble characteristics of the HD700. We recommend taking regular breaks to check for any discomfort, ringing, deafness, or nausea. This advice is not restricted to the HD700, but all other headphones with similar characteristics such as the more aggressive Grados, Ultrasones, and some Beyers.
Pricing
We make no value judgement on the price of the HD700. However, we would urge anyone considering this headphone to do at least of one of the following: 1) Try headphones of comparable quality (of lesser or even higher cost); 2) Examine characteristics of well known good headphones.
HD700 vs. LCD2r2 @ $995.
HD700 (green) vs. LCD2r2 (red)
LCD2R2 vs. HD700 CSD Plot (midrange to treble)
While we have been highly critical in the past of the QC issues related to these headphones, we feel that Audeze has finally nailed it down. The LCD2 is now mature technology. The sound of the LCD2 is consistent from unit to unit. Sennheiser has always been very consistent with good quality control throughout their headphone line-up. Although it should be noted that a few owners have had some issues with the earcup pivots of the HD700.
The LCD2 is not as rolled-off as people think. The LCD2 has neutral and significantly cleaner sounding lower extending bass than the HD700. The LCD2 has the tiniest bit of harshness in the lower treble (much improved from the r1) which makes it sound less refined compared to better TOTL cans, but we are just being extremely nit-picky. However, the slightly shelved down upper midrange and treble of the LCD2 may not sit well for some people. There is some truth that the LCD2 sounds better with popular music than classical. I'm sure many classical listeners who own the LCD2 like it because it is well behaved. Classical music listeners may well prefer the HD700 to the LCD2. Listeners who prefer a more “detailed” direct forward presentation may also prefer the HD700.
We had no problems driving the LCD2. They are not difficult to match with. The HD700 may need some care. The more solid-state sounding tubes (KR PX4 or EML 300B) did not fare as well as the rare Osram PX25 which is known to have a very silky sounding treble.
HD700 vs. HE500 @ $699.
HD700 (green) vs. HE500 (red)
The 6kHz dip in HE500 is an artifact from grill/headphone cup interactions.
HE-500 vs HD700 CSD Plot (midrange to treble)
The HE500 is fairly neutral, maybe dark depending upon amplification and upstream gear. It does have a slightly broad treble bump at 10k, not unlike the better T50RP modded headphones. But this coloration, because it not excessive, can actually be desirable. It gives recordings more definition, but at the cost of more apparent noise and stridency. The HD700 also has a rise at 11kHz, but its characteristic is peakier and not as broad. The magnitude of the 11kHz peak with the HD700 is also higher. The HE500’s bump is more benign compared to the HD700’s peak which is more “spotlit.”
The frequency response of the HE500 is otherwise very smooth. Some people have commented that it has a speaker like presentation. This is because it has no upper midrange or treble resonances. The most major criticism of the HE500 is that the bass is sometimes uncontrolled and does extend down to the lowest octave. The HD700 bass is better controlled and extends slightly lower. The HE500 is great headphone for all sorts of music. It also does not have special amplification requirements.
HD700 vs. ESP950 @ $620 (includes amp)
HD700 (green) vs. ESP950 (red)
ESP950 vs. HD700 CSD Plot (midrange to treble)
The ESP950 has a midbass bump and apparent forward presentation. It is a very neutral headphone with electrostatic speed and transient response which the HD700 cannot hope to match. The ESP950 are not supremely resolving and do not reproduce micro-detail very well, so the HD700 may win by a hair in this category.
The ESP950 is a great headphone for all sorts of music but does really well with classical, certain types of rock, or jazz (recordings which don't hit the lowest bass octave often.) The ESP950 didn’t stop me from listening to Rage Against the Machine. Those who want lower, louder, and more tactile bass may prefer the HD700, but this will be at the expense of the ESP950s extremely smooth and well behaved response.
When I got my stat amp, but didn't have any other headphone available, I listened to these for two days in a row, 14 hours each day, sometimes at almost realistic volume levels 92-95db, without losing my hearing. This would not have been possible with the HD700.
The included amp is surprisingly decent.
HD700 vs. HD650 @ $479.
HD700 (green) vs. HD650 (red)
HD650 vs. HD700 CSD Plot (midrange to treble)
Since many people are familiar with the HD650, I figure I don't need to say much about these. The HD650 have muddy bass compared to the HD700. Some people think the HD650 sounds veiled because the lower treble is scooped (the rest of the treble isn't though!) The HD650 is a very pleasant relaxing listen which can offer gobs of low-level information and micro-detail with good upstream equipment. The HD700 while having more apparent gross detail, does not offer any better micro-detail. The HD700’s treble characteristics are almost in directly opposite of that the HD650s’.
HD700 vs. HE400 @ $399
HD700 (blue) vs. HD650 (green)
The HE400's bass sounds tight and snappy (better than the HE500). It can be a bassy sounding headphone (dependent upon recording and upstream gear), but hardly veiled akin to the HD650 (if it ever was.) The upper midrange is sucked out, but it's difficult to notice because there's significant treble energy and air. Depending upon the nature of the recording that we are listening to, the HE400 can sound either dark or bright. My favorite characteristic was how laid-back everything sounded without being dull or veiled. I didn't hear any ringing or peaks in the upper midrange or treble despite the jaggyness in response, which seems to be an ortho trait. The entire range of the HE400 sounded more cohesive than the HD700. The downside of the HE400 is that instruments and voices can lack bite, snappiness, or attack. This is opposite to the HD700's approach. (We can see these differences of approach around 5.5kHz on the frequency response graphs.) The HD700 is better than the HE400 in apparent gross detail, and possibly micro-detail, but only by a bit. The HE400 has cleaner lower bass reproduction. There was perhaps a bump in the HE400's midrange that accounted for a nasal quality with voices on certain tracks.
DT990-600 @ $272
Finally got a chance to listen to these. Unlike most or any Beyer I've heard so far, it sounds fairly well behaved and not as hot as the T1 in the treble. Good bass. Slight U-curve FR as with the HD700. The HD700 outclasses it in terms of micro-detail and clarity. But the DT990-600 sounds more cohesive with a purer midrange. Tubes were able to take the edge of the DT-990-600 treble (heard this on Lyr and Vahalla.)
Now taking questions...
Edited by purrin - 8/22/12 at 10:21pm
